The present invention relates generally to a method for converting carcinogenic asbestos waste material into non-carcinogenic and relatively non-hazardous compounds, and more particularly to the conversion of such asbestos material by fully fluorinating the crystalline fibrous silicate mineral defining the asbestos material for the transformation thereof into a silicon-free, non-crystalline solid compound and gaseous compounds.
Historically, asbestos, as defined by various impure silicate minerals characterized by crystalline fibrous structures, has been extensively utilized as thermal and electrical insulation and as a building material because of its insulating and fire-proof properties. Generally, two types of asbestos have been used in the United States for such purposes. The first and most common type of asbestos used is the so-called serpentine asbestos or chrysotile which is a magnesium silicate mineral possessing relatively long and flexible crystalline fibers which can be readily formed into mats and weavings and other desired configurations for use in building construction or in thermal and electrical insulation applications. The second type of asbestos used is amphibole asbestos formed of the silicate minerals, tremolite, actinolite, anthophyllite, and crocidolite. An amphibole asbestos is characterized by a hydroxyl, a silicon-to-oxygen ratio of 4 to 11, and a fibrous cleavage. The crystalline fibers of amphibole asbestos are substantially more brittle than the chrysotile asbestos fibers so as to somewhat limit the fabrication of amphibole asbestos into selected shapes.
Relatively recent investigations have demonstrated that asbestos is both a hazardous material capable of causing asbestosis, a pneumoconiosis produced by inhalation of fibrous asbestos particles, and a carcinogen capable of causing various forms of cancer. Because of these highly undesirable properties of asbestos, a considerable effort is currently being made to remove asbestos materials from buildings, especially schools and public buildings. This extensive asbestos removal program has resulted in a considerable amount of waste asbestos material which is presently disposed of by encasing the asbestos in suitable containment structures formed of a durable material such as plastic and then disposing the contained asbestos in an approved landfill. These present disposal methods of asbestos material are not only costly with respect to the manpower required for preparing the waste for disposal and for the possible eternal control over the landfill but also deny the use of large areas of land for any other purpose.